In recent years, in accordance with a rapid spread of information relevant apparatuses such as a personal computer, a video camera and a portable telephone, the development of a battery to be utilized as a power source thereof has been active. The development of a high-output and high-capacity battery for an electric automobile or a hybrid automobile has been advanced also in the automobile industry. A lithium ion battery has the advantage that energy density is high among various kinds of batteries.
Liquid electrolyte containing a flammable organic solvent is used for a presently commercialized lithium ion battery, so that a device for restraining temperature rise during a short circuit and a device for preventing the short circuit are necessary therefor. In contrast, a lithium solid state battery all-solidified by replacing the liquid electrolyte with a solid electrolyte layer intends the simplification of the safety device and is excellent in production cost and productivity for the reason that the flammable organic solvent is not used in the battery.
Various methods are known as a method for forming a solid electrolyte layer. In Patent Literature 1, a method for producing a sulfide-based solid state battery, in which sulfide-based solid electrolyte slurry containing a sulfide-based solid electrolyte, a binder and a fatty acid ester is prepared and coated on one electrode to form an electrolyte layer and laminate the other electrode on the electrolyte layer, is disclosed. Also, in Patent Literature 2, a blast method and an aerosol deposition method are exemplified as a method for forming an electrolyte with a membrane thickness of 500 μm or less, composed substantially of only a lithium ion conductive solid substance.
Also, in Patent Literature 3, a blast method, an aerosol deposition method, a cold spray method, a sputtering method, a vapor growth method and a thermal spraying method are exemplified as a method for forming a solid electrolyte layer. Also, in Patent Literature 4, a method for producing a nonaqueous electrolyte battery, in which a cathode body having an amorphous cathode side solid electrolyte layer on a cathode active material and an anode body having an amorphous anode side solid electrolyte layer on an anode active material layer are prepared and heat-treated while superposing the cathode side solid electrolyte layer and the anode side solid electrolyte layer so as to contact with each other, and bonded by crystallizing the cathode side solid electrolyte layer and the anode side solid electrolyte layer, is disclosed. Incidentally, in Patent Literature 4, a vacuum deposition method, a sputtering method, an ion plating method and a laser ablation method are disclosed as a method for forming the cathode side solid electrolyte layer (PSE layer).